1. Field of the Invention
The present invention relates to an image processing or an image compressing or expanding technology for a rectangular image data (packet data) in a controller for a multifunction system applicable to a copying apparatus, a printer etc.
2. Related Background Art
In a controller of a conventional multifunction system applicable to a copying apparatus or a printer, image data are processed as a raster image, and the image processing or the image compression/expansion is executed in a unit of a raster image of a page.
There is also known a controller which divides the image data into packets and executes image processing in the unit of each packet, thereby executing image processing to the packet data in parallel manner.
As the image processing has conventionally been executed in the unit of a page, a single process requires a time for completion and it has been difficult to process plural images at the same time. Such drawback becomes conspicuous particularly in case of handling a color image, since the data amount per page becomes larger. Also in case of executing compression/expansion of the image in the unit of a page, it is necessary to expand/compress the entire image even for processing only a part of a page, whereby the processing time increases.
Also in case of parallel image processing, since the processing is executed in divided manner in the unit of a pixel or a line, such process is unsuitable for the image processing in the unit of a block. Also in case of image processing in parallel manner in the unit of packet data, a change in the image processing mode in an image processing unit has to be made from a CPU. Therefore, such process is unsuitable for executing image processing in parallel manner for plural images of mutually different process modes. As a result, there results a prolongation of the image processing time or an increase in the burden of the CPU.